cmStandardIncludes: Remove MSVC6 condition for cmArrayBegin macro.

Source/cmStandardIncludes.h

@@ -393,8 +393,7 @@ inline bool cmHasLiteralSuffixImpl(const char* str1,
   return len >= N && strcmp(str1 + len - N, str2) == 0;
 }
 
-#if defined(_MSC_VER) && _MSC_VER < 1300 \
-  || defined(__GNUC__) && __GNUC__ < 3
+#if defined(__GNUC__) && __GNUC__ < 3
 
 #define cmArrayBegin(a) a
 #define cmArraySize(a) (sizeof(a)/sizeof(*a))